Revelation 21:12-17

12It had a great, high wall with twelve gates, and with twelve angels at the gates. On the gates were written the names of the twelve tribes of Israel. 13There were three gates on the east, three on the north, three on the south and three on the west.

14The wall of the city had twelve foundations, and on them were the names of the twelve apostles of the Lamb. 15The angel who talked with me had a measuring rod of gold to measure the city, its gates and its walls. 16The city was laid out like a square, as long as it was wide. He measured the city with the rod and found it to be 12,000 stadia That is, about 1,400 miles or about 2,200 kilometers in length, and as wide and high as it is long. 17The angel measured the wall using human measurement, and it was 144 cubits That is, about 200 feet or about 65 meters thick. Or high